(1) Field of Invention
The present invention relates to a (a) novel dicarboxylated surfactant, (b) a method for the preparation of said dicarboxylated surfactant and (c) application of said dicarboxylated surfactants in industrial and personal care applications.
The compounds of the present invention are made by reacting epoxy succinic acid and a salt of an alkyl alkoxylated surfactant, followed by neutralization in aqueous solution, if desired. The resulting compound is quite stable very mild to hair and skin and offers excellent surfactant properties, including detergency and foam. In addition, compounds of the present invention containing a pendant hydroxyl group which alters the water solubility and emulsification properties of the compound.
(2) Object of the Invention
It is the object of the present invention to provide novel a process for the preparation of surface active agents that are well tolerated by skin and eyes. These non-irritating products produce copious foam, have outstanding emulsification properties and are ideal products for use in the formulation of hair and skin care products like shampoos, conditioners and body washes.
(3) Description of the Arts and Practices
U.S. Pat. No. 4,065,475 to Hosi et al issued in December of 1977 discloses a process for preparation of cis epoxy succinic acid, a raw material for the preparation of the compounds of the present invention. This material is easily made by the reaction of maleic acid with hydrogen peroxide in the presence of a tungsten catalyst. The availability of this high purity raw material is very critical in the preparation of the compounds of the present invention.
The compounds of the present invention are made by reacting cis epoxy succinic acid with a salt of an alkyl alkoxylated surfactant, followed by neutralization in aqueous solution if desired. The resulting compound is an outstanding surfactant for personal care applications.
The compounds of the present invention have several key portions in the molecule. Those groups include (a) an alkyl group, (b) a hydroxy linkage group and (c) two carboxy groups that improve water solubility and emulsification properties. These groups and their positioning in the molecule result in unique properties for the molecule. These include foam, detergency, chelation properties (especially for calcium ion), emulsification properties, wetting properties, particularly for hydrophobic pigments, and a lubricious skin feel. This combination of properties has heretofore been unattainable in one molecule.
Compounds of the invention conform to the following structure: 
wherein;
R1 is CH3(CH2)sxe2x80x94Oxe2x80x94(CH2CH2xe2x80x94O)zxe2x80x94(CH2CH(CH3)O)yxe2x80x94(CH2CH2xe2x80x94O)x;
s is an integer ranging from 3 to 21;
x, y and z are independently integers ranging from 0 to 20 with the proviso that x+y+z equal at least 1;
M is selected from the group consisting of H, Na, K, Li, and NH4.
Illustrative of the sequence for the preparation of the compounds of the present is as follows;
3 moles of sodium methylate (25% in methanol) is added to a mixture of 1 mole of alkoxylated non-ionic surfactant and one mole of epoxy succinic acid. This results in the formation of the indicated salts and the formation of the alkoxide ion of the non-ionic. The alkoxide ion reacts to open the epoxide.
CH3(CH2)11(CH2CH2O)7xe2x80x94H+3CH3ONaxe2x86x92sodium methylate
CH3(CH2)11(CH2CH2O)7xe2x88x92Na++3 CH3OH Alkoxide ion

The compounds of the present invention are very good ingredients in a variety of applications due to the presence of both the two carboxyl groups. These applications include:
(a) emulsion polymerization;
(b) urethane foams as modifiers of bubble structure;
(c) pigment dispersion agents for hydrophobic pigments;
(d) personal care applications for excellent skin feel.
They are outstanding emulsifiers and wetting agents.
Preferred Embodiments
In a preferred embodiment s is 3.
In a preferred embodiment s is 5.
In a preferred embodiment s is 7.
In a preferred embodiment s is 9.
In a preferred embodiment s is 11.
In a preferred embodiment s is 13.
In a preferred embodiments is 16.
In a preferred embodiment x ranges from 3 to 10.
In a preferred embodiment y ranges from 1 to 10.
In a preferred embodiment s is 11 and x ranges from 3 to 10.
In a preferred embodiment s is 13 and x ranges from 3 to 10.
In a preferred embodiment s is 15 and x ranges from 3 to 10.